JPH0334509Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a resonance prevention device for a cam damper that converts rotational fluctuations into the thrust direction to obtain a damper effect.

[Technical background of the invention and its problems]

BACKGROUND OF THE INVENTION Engine drive systems such as motorcycles are often equipped with a damper mechanism that absorbs engine torque fluctuations in order to prevent meshing noise of gears built into the system and torsional resonance of the shaft. in this case,
By using a cam damper loaded with disc springs, a compact and large-capacity damper performance can be obtained. An example is shown in FIG. Crankshaft 1 and countershaft 3
An intermediate shaft 2 is arranged in parallel between the two, and a driven gear 5 rotatably supported by the intermediate shaft 2 and a drive gear 4 fixed to the crankshaft 1 are meshed with each other. As shown in FIG. 3, a projection 6 is formed on the boss 5a of the driven gear 5 so as to project in the axial direction. On the other hand, adjacent to the driven gear 5, a slide cam 7 that rotates integrally with the slide cam 7 and is slidable in the axial direction is pivotally supported by the intermediate shaft 2. A cam surface 8 recessed in a U-shape in the axial direction is formed on the end surface of the slide cam 7 facing the driven gear 5, and the tip of the projection 6 comes into contact with the cam surface 8. A disc spring 9 is elastically loaded on the back surface of the slide cam 7 and presses the cam surface 8 and the projection 6. A primary drive gear 10 is fixed to the end of the intermediate shaft 2 and meshes with a primary driven gear 11 freely supported on the counter shaft 3. The primary driven gear 11 and the counter shaft 3 are coupled via a friction clutch 12, and the counter shaft 3 and the output shaft 1 are connected to each other via a friction clutch 12.
3 and 3, transmission gear trains 14 and 15 (not shown with some parts omitted) are meshed with each other, and deceleration is selected to provide rotation.

With the above configuration, the torque generated on the crankshaft 1 is transmitted to the transmission system below the primary drive gear 10 via the cam damper on the intermediate shaft 2. The transmitted torque of the cam damper produces an axial component force by the cam surface 8 and is balanced by the disc spring 9. When a torque fluctuation occurs on the crankshaft 1, the slide cam 7 causes a rotational fluctuation between the protrusion 6 and the cam surface 8.
A large damper effect is obtained by varying the axial direction.

However, such a disc spring 9 has a natural frequency, which resonates with the frequency of torque fluctuation, causing a problem that abnormal noise is generated in the conduction system.

[Purpose of invention]

In view of the above-mentioned problems, this invention aims to prevent the resonance of the disc spring loaded with the cam damper.

[Summary of the idea]

In order to achieve the above object, the cam damper resonance prevention device of this invention is provided by separating the transmission system into two relatively rotatable rotating members on the same axis, and fixing it to one of the rotating members. A fixed cam that is not movable in the axial direction and a slide cam that is rotatable and slidable in the axial direction and that is pivotally supported on the other rotating member are slidably contacted by a cam surface that is inclined in the axial direction in the circumferential direction. In a cam damper in which the slide cam is pressed against the fixed cam by a spring loaded on the back of the slide cam, a disc spring is loaded on the slide cam, and the spring constant of the disc spring is It is characterized by a structure in which coil springs with a small spring constant are elastically loaded in parallel.

[Example of idea]

FIG. 1 shows an embodiment of this invention.

A gear 21 is rotatably supported on a shaft 22, with the gear 21 on the drive side and the shaft 22 on the driven side,
A cam damper is interposed between the two. That is, a fixed cam 24 protruding in the axial direction is formed on the surface of the boss 23 of the gear 21. On the other hand, a slide cam 25 that rotates integrally with the shaft 22 and is slidable in the axial direction is pivotally supported, and a U-shape provided on the end surface of the fixed cam 24 is formed on the surface of the boss 23 of the gear 21. The fixed cam 24 faces inside the shaped cam surface 26. A disc spring 27 is elastically loaded on the back surface of the slide cam 25, and presses the fixed cam 24 and the cam surface 26. When a sudden torque fluctuation occurs in the gear 21, the force is converted in the axial direction by the inclination of the cam surface 26, and the disc spring 27 acts to buffer it.

Next, a coil spring 28 is elastically mounted on the tail end 25a of the slide cam 25. coil spring 2
8 has a sufficiently smaller spring constant than that of the disc spring 27. Therefore, torque is normally transmitted mainly by the stress of the disc spring 27.

The torque fluctuation frequency of the transmitted torque is
7, the disc spring 27 resonates. At this time, the disc spring 27 is timid and becomes the same state as if the load had disappeared, but the stored force of the coil spring 28 applied to the slide cam 25 acts as a damper, preventing the above-mentioned resonance. .

[Effect of idea]

As mentioned above, the resonance prevention device for a cam damper according to this invention consists of a disc spring mounted on the cam damper, and a coil spring with a sufficiently small spring constant compared to the disc spring, which is normally compressed. When the disc spring resonates, it acts to damp the vibration and prevent resonance. The simple structure of adding a small coil spring with a small spring constant does not affect the compactness or functionality of the cam damper, and prevents abnormal noise and damage accidents caused by resonance of this type of cam damper.
It has the effect of greatly improving the functionality and durability of engine transmission systems, etc.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a cam damper showing an embodiment of this invention, FIG. 2 is a sectional view of an engine transmission system illustrating a conventional cam damper, and FIG. 3 is an enlarged plan view of the same cam damper. 21... Gear, 22... Shaft, 24... Fixed cam, 25... Slide cam, 26... Cam surface, 2
7... disc spring, 28... coil spring.

Claims (1)

[Scope of utility model registration request] The transmission system is separated into two rotating members on the same axis that are rotatable relative to each other, with a fixed cam that is fixed to one rotating member and not moving in the axial direction, and a rotating member that is pivoted to the other rotating member. The slide cam, which is integrally slidable in the axial direction, is brought into sliding contact with the cam surface inclined in the axial direction toward the circumferential direction, and the slide cam is moved by a spring loaded on the back of the slide cam. A cam damper configured to press against a fixed cam is characterized in that the slide cam is loaded with a disc spring, and a coil spring with a spring constant sufficiently smaller than the spring constant of the disc spring is loaded in parallel. Cam damper resonance prevention device.